With the growth of information communication technology, various wireless communication technologies are under development. Among the wireless communication technologies, wireless local area network (WLAN) technology enables wireless Internet access at home or in offices or specific service provision areas using a mobile terminal such as a personal digital assistant (PDA), laptop computer, portable multimedia player (PMP) or the like on the basis of radio frequency technology.
To overcome the limitations of communication rate, which have been blamed for a weak point of WLAN, recent technical standards have introduced systems with increased network rate and reliability and extended wireless network coverage. For example, IEEE 802.11n supports high throughput (HT) of a data rate of 540 Mbps or higher and introduces MIMO (Multiple Input Multiple Output) technology which uses multiple antennas for both a transmitter and a receiver in order to minimize a transmission error and optimize a data rate.
IEEE 802.11ai is developed as new standards for supporting fast initial link setup for stations (STAs) that support IEEE 802.11 at a MAC (Medium Access Control) layer of IEEE 802.11 systems. IEEE 802.11ai aims to provide technologies for supporting high-speed link setup in a situation in which so many people leave previously connected WLAN coverage and substantially simultaneously access a new WLAN in the case of public transportation transfer, for example. In addition, IEEE 803.11ai has characteristics of security framework, IP address assignment, fast network discovery, etc.